Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual foi o resultado quando o oponente era Serena Williams, Venus Williams e a superfície era dura?
 ###Tabelas: CREATE TABLE current_rolling_stock (current_rolling_stock_id AUTO_INCREMENT PRIMARY KEY, Class VARCHAR, Introduced VARCHAR, Number in class INT, Number in service INT, Power output (kW) INT) CREATE TABLE waterford_and_limerick_railway (waterford_and_limerick_railway_id AUTO_INCREMENT PRIMARY KEY, Year VARCHAR, Type VARCHAR, Nos. VARCHAR, GSWR Class INT, GSWR Nos. VARCHAR, GSR Class VARCHAR, Inchicore Class VARCHAR, Withdrawn VARCHAR) CREATE TABLE list_of_wisden_trophy_series (list_of_wisden_trophy_series_id AUTO_INCREMENT PRIMARY KEY, Series VARCHAR, Season VARCHAR, Host VARCHAR, Tests INT, England INT, West Indies INT, Draw INT, Series result VARCHAR, Holder at the end of the series VARCHAR) CREATE TABLE women's_doubles:_10_finals_3_titles_7_runner-ups (women's_doubles:_10_finals_3_titles_7_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents in the final VARCHAR, Score in the final VARCHAR) CREATE TABLE tallest_completed_buildings (tallest_completed_buildings_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Height (m) INT, Height (ft) INT, Location VARCHAR, Year built INT)  
SELECT Outcome FROM women's_doubles:_10_finals_3_titles_7_runner-ups WHERE Opponents in the final = serena williams venus williams AND Surface = hard